Timeline out of sync

[B.M.]

Dear all,

I have a strange problem since today: in my project, a clip (let's call it
clip.mp4) is part of the timeline, showing its name "clip.mp4", when I right
click, then Clip in Project Bin, clip.mp4 is shown in the clip monitor. But
when I play the timeline, instead of clip.mp4, another clip is played (let's
call it other.mp4). How is this possible and can it be fixed somehow?

When doing a Preview Render of this section, also other.mp4 is used.

Thanks for any help.

Best,
Bernd